/*
 * A speed-improved perlin and simplex noise algorithms for 2D.
 *
 * Based on example code by Stefan Gustavson (stegu@itn.liu.se).
 * Optimisations by Peter Eastman (peastman@drizzle.stanford.edu).
 * Better rank ordering method by Stefan Gustavson in 2012.
 * Converted to Javascript by Joseph Gentle.
 *
 * Version 2012-03-09
 *
 * This code was placed in the public domain by its original author,
 * Stefan Gustavson. You may use it as you see fit, but
 * attribution is appreciated.
 *
 */

;(function (global) {
  var module = (global.noise = {})

  function Grad(x, y, z) {
    this.x = x
    this.y = y
    this.z = z
  }

  Grad.prototype.dot2 = function (x, y) {
    return this.x * x + this.y * y
  }

  Grad.prototype.dot3 = function (x, y, z) {
    return this.x * x + this.y * y + this.z * z
  }

  var grad3 = [
    new Grad(1, 1, 0),
    new Grad(-1, 1, 0),
    new Grad(1, -1, 0),
    new Grad(-1, -1, 0),
    new Grad(1, 0, 1),
    new Grad(-1, 0, 1),
    new Grad(1, 0, -1),
    new Grad(-1, 0, -1),
    new Grad(0, 1, 1),
    new Grad(0, -1, 1),
    new Grad(0, 1, -1),
    new Grad(0, -1, -1),
  ]

  var p = [
    151,
    160,
    137,
    91,
    90,
    15,
    131,
    13,
    201,
    95,
    96,
    53,
    194,
    233,
    7,
    225,
    140,
    36,
    103,
    30,
    69,
    142,
    8,
    99,
    37,
    240,
    21,
    10,
    23,
    190,
    6,
    148,
    247,
    120,
    234,
    75,
    0,
    26,
    197,
    62,
    94,
    252,
    219,
    203,
    117,
    35,
    11,
    32,
    57,
    177,
    33,
    88,
    237,
    149,
    56,
    87,
    174,
    20,
    125,
    136,
    171,
    168,
    68,
    175,
    74,
    165,
    71,
    134,
    139,
    48,
    27,
    166,
    77,
    146,
    158,
    231,
    83,
    111,
    229,
    122,
    60,
    211,
    133,
    230,
    220,
    105,
    92,
    41,
    55,
    46,
    245,
    40,
    244,
    102,
    143,
    54,
    65,
    25,
    63,
    161,
    1,
    216,
    80,
    73,
    209,
    76,
    132,
    187,
    208,
    89,
    18,
    169,
    200,
    196,
    135,
    130,
    116,
    188,
    159,
    86,
    164,
    100,
    109,
    198,
    173,
    186,
    3,
    64,
    52,
    217,
    226,
    250,
    124,
    123,
    5,
    202,
    38,
    147,
    118,
    126,
    255,
    82,
    85,
    212,
    207,
    206,
    59,
    227,
    47,
    16,
    58,
    17,
    182,
    189,
    28,
    42,
    223,
    183,
    170,
    213,
    119,
    248,
    152,
    2,
    44,
    154,
    163,
    70,
    221,
    153,
    101,
    155,
    167,
    43,
    172,
    9,
    129,
    22,
    39,
    253,
    19,
    98,
    108,
    110,
    79,
    113,
    224,
    232,
    178,
    185,
    112,
    104,
    218,
    246,
    97,
    228,
    251,
    34,
    242,
    193,
    238,
    210,
    144,
    12,
    191,
    179,
    162,
    241,
    81,
    51,
    145,
    235,
    249,
    14,
    239,
    107,
    49,
    192,
    214,
    31,
    181,
    199,
    106,
    157,
    184,
    84,
    204,
    176,
    115,
    121,
    50,
    45,
    127,
    4,
    150,
    254,
    138,
    236,
    205,
    93,
    222,
    114,
    67,
    29,
    24,
    72,
    243,
    141,
    128,
    195,
    78,
    66,
    215,
    61,
    156,
    180,
  ]
  // To remove the need for index wrapping, double the permutation table length
  var perm = new Array(512)
  var gradP = new Array(512)

  // This isn't a very good seeding function, but it works ok. It supports 2^16
  // different seed values. Write something better if you need more seeds.
  module.seed = function (seed) {
    if (seed > 0 && seed < 1) {
      // Scale the seed out
      seed *= 65536
    }

    seed = Math.floor(seed)
    if (seed < 256) {
      seed |= seed << 8
    }

    for (var i = 0; i < 256; i++) {
      var v
      if (i & 1) {
        v = p[i] ^ (seed & 255)
      } else {
        v = p[i] ^ ((seed >> 8) & 255)
      }

      perm[i] = perm[i + 256] = v
      gradP[i] = gradP[i + 256] = grad3[v % 12]
    }
  }

  module.seed(0)

  /*
  for(var i=0; i<256; i++) {
    perm[i] = perm[i + 256] = p[i];
    gradP[i] = gradP[i + 256] = grad3[perm[i] % 12];
  }*/

  // Skewing and unskewing factors for 2, 3, and 4 dimensions
  var F2 = 0.5 * (Math.sqrt(3) - 1)
  var G2 = (3 - Math.sqrt(3)) / 6

  var F3 = 1 / 3
  var G3 = 1 / 6

  // 2D simplex noise
  module.simplex2 = function (xin, yin) {
    var n0, n1, n2 // Noise contributions from the three corners
    // Skew the input space to determine which simplex cell we're in
    var s = (xin + yin) * F2 // Hairy factor for 2D
    var i = Math.floor(xin + s)
    var j = Math.floor(yin + s)
    var t = (i + j) * G2
    var x0 = xin - i + t // The x,y distances from the cell origin, unskewed.
    var y0 = yin - j + t
    // For the 2D case, the simplex shape is an equilateral triangle.
    // Determine which simplex we are in.
    var i1, j1 // Offsets for second (middle) corner of simplex in (i,j) coords
    if (x0 > y0) {
      // lower triangle, XY order: (0,0)->(1,0)->(1,1)
      i1 = 1
      j1 = 0
    } else {
      // upper triangle, YX order: (0,0)->(0,1)->(1,1)
      i1 = 0
      j1 = 1
    }
    // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
    // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
    // c = (3-sqrt(3))/6
    var x1 = x0 - i1 + G2 // Offsets for middle corner in (x,y) unskewed coords
    var y1 = y0 - j1 + G2
    var x2 = x0 - 1 + 2 * G2 // Offsets for last corner in (x,y) unskewed coords
    var y2 = y0 - 1 + 2 * G2
    // Work out the hashed gradient indices of the three simplex corners
    i &= 255
    j &= 255
    var gi0 = gradP[i + perm[j]]
    var gi1 = gradP[i + i1 + perm[j + j1]]
    var gi2 = gradP[i + 1 + perm[j + 1]]
    // Calculate the contribution from the three corners
    var t0 = 0.5 - x0 * x0 - y0 * y0
    if (t0 < 0) {
      n0 = 0
    } else {
      t0 *= t0
      n0 = t0 * t0 * gi0.dot2(x0, y0) // (x,y) of grad3 used for 2D gradient
    }
    var t1 = 0.5 - x1 * x1 - y1 * y1
    if (t1 < 0) {
      n1 = 0
    } else {
      t1 *= t1
      n1 = t1 * t1 * gi1.dot2(x1, y1)
    }
    var t2 = 0.5 - x2 * x2 - y2 * y2
    if (t2 < 0) {
      n2 = 0
    } else {
      t2 *= t2
      n2 = t2 * t2 * gi2.dot2(x2, y2)
    }
    // Add contributions from each corner to get the final noise value.
    // The result is scaled to return values in the interval [-1,1].
    return 70 * (n0 + n1 + n2)
  }

  // 3D simplex noise
  module.simplex3 = function (xin, yin, zin) {
    var n0, n1, n2, n3 // Noise contributions from the four corners

    // Skew the input space to determine which simplex cell we're in
    var s = (xin + yin + zin) * F3 // Hairy factor for 2D
    var i = Math.floor(xin + s)
    var j = Math.floor(yin + s)
    var k = Math.floor(zin + s)

    var t = (i + j + k) * G3
    var x0 = xin - i + t // The x,y distances from the cell origin, unskewed.
    var y0 = yin - j + t
    var z0 = zin - k + t

    // For the 3D case, the simplex shape is a slightly irregular tetrahedron.
    // Determine which simplex we are in.
    var i1, j1, k1 // Offsets for second corner of simplex in (i,j,k) coords
    var i2, j2, k2 // Offsets for third corner of simplex in (i,j,k) coords
    if (x0 >= y0) {
      if (y0 >= z0) {
        i1 = 1
        j1 = 0
        k1 = 0
        i2 = 1
        j2 = 1
        k2 = 0
      } else if (x0 >= z0) {
        i1 = 1
        j1 = 0
        k1 = 0
        i2 = 1
        j2 = 0
        k2 = 1
      } else {
        i1 = 0
        j1 = 0
        k1 = 1
        i2 = 1
        j2 = 0
        k2 = 1
      }
    } else {
      if (y0 < z0) {
        i1 = 0
        j1 = 0
        k1 = 1
        i2 = 0
        j2 = 1
        k2 = 1
      } else if (x0 < z0) {
        i1 = 0
        j1 = 1
        k1 = 0
        i2 = 0
        j2 = 1
        k2 = 1
      } else {
        i1 = 0
        j1 = 1
        k1 = 0
        i2 = 1
        j2 = 1
        k2 = 0
      }
    }
    // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
    // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
    // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
    // c = 1/6.
    var x1 = x0 - i1 + G3 // Offsets for second corner
    var y1 = y0 - j1 + G3
    var z1 = z0 - k1 + G3

    var x2 = x0 - i2 + 2 * G3 // Offsets for third corner
    var y2 = y0 - j2 + 2 * G3
    var z2 = z0 - k2 + 2 * G3

    var x3 = x0 - 1 + 3 * G3 // Offsets for fourth corner
    var y3 = y0 - 1 + 3 * G3
    var z3 = z0 - 1 + 3 * G3

    // Work out the hashed gradient indices of the four simplex corners
    i &= 255
    j &= 255
    k &= 255
    var gi0 = gradP[i + perm[j + perm[k]]]
    var gi1 = gradP[i + i1 + perm[j + j1 + perm[k + k1]]]
    var gi2 = gradP[i + i2 + perm[j + j2 + perm[k + k2]]]
    var gi3 = gradP[i + 1 + perm[j + 1 + perm[k + 1]]]

    // Calculate the contribution from the four corners
    var t0 = 0.6 - x0 * x0 - y0 * y0 - z0 * z0
    if (t0 < 0) {
      n0 = 0
    } else {
      t0 *= t0
      n0 = t0 * t0 * gi0.dot3(x0, y0, z0) // (x,y) of grad3 used for 2D gradient
    }
    var t1 = 0.6 - x1 * x1 - y1 * y1 - z1 * z1
    if (t1 < 0) {
      n1 = 0
    } else {
      t1 *= t1
      n1 = t1 * t1 * gi1.dot3(x1, y1, z1)
    }
    var t2 = 0.6 - x2 * x2 - y2 * y2 - z2 * z2
    if (t2 < 0) {
      n2 = 0
    } else {
      t2 *= t2
      n2 = t2 * t2 * gi2.dot3(x2, y2, z2)
    }
    var t3 = 0.6 - x3 * x3 - y3 * y3 - z3 * z3
    if (t3 < 0) {
      n3 = 0
    } else {
      t3 *= t3
      n3 = t3 * t3 * gi3.dot3(x3, y3, z3)
    }
    // Add contributions from each corner to get the final noise value.
    // The result is scaled to return values in the interval [-1,1].
    return 32 * (n0 + n1 + n2 + n3)
  }

  // ##### Perlin noise stuff

  function fade(t) {
    return t * t * t * (t * (t * 6 - 15) + 10)
  }

  function lerp(a, b, t) {
    return (1 - t) * a + t * b
  }

  // 2D Perlin Noise
  module.perlin2 = function (x, y) {
    // Find unit grid cell containing point
    var X = Math.floor(x),
      Y = Math.floor(y)
    // Get relative xy coordinates of point within that cell
    x = x - X
    y = y - Y
    // Wrap the integer cells at 255 (smaller integer period can be introduced here)
    X = X & 255
    Y = Y & 255

    // Calculate noise contributions from each of the four corners
    var n00 = gradP[X + perm[Y]].dot2(x, y)
    var n01 = gradP[X + perm[Y + 1]].dot2(x, y - 1)
    var n10 = gradP[X + 1 + perm[Y]].dot2(x - 1, y)
    var n11 = gradP[X + 1 + perm[Y + 1]].dot2(x - 1, y - 1)

    // Compute the fade curve value for x
    var u = fade(x)

    // Interpolate the four results
    return lerp(lerp(n00, n10, u), lerp(n01, n11, u), fade(y))
  }

  // 3D Perlin Noise
  module.perlin3 = function (x, y, z) {
    // Find unit grid cell containing point
    var X = Math.floor(x),
      Y = Math.floor(y),
      Z = Math.floor(z)
    // Get relative xyz coordinates of point within that cell
    x = x - X
    y = y - Y
    z = z - Z
    // Wrap the integer cells at 255 (smaller integer period can be introduced here)
    X = X & 255
    Y = Y & 255
    Z = Z & 255

    // Calculate noise contributions from each of the eight corners
    var n000 = gradP[X + perm[Y + perm[Z]]].dot3(x, y, z)
    var n001 = gradP[X + perm[Y + perm[Z + 1]]].dot3(x, y, z - 1)
    var n010 = gradP[X + perm[Y + 1 + perm[Z]]].dot3(x, y - 1, z)
    var n011 = gradP[X + perm[Y + 1 + perm[Z + 1]]].dot3(x, y - 1, z - 1)
    var n100 = gradP[X + 1 + perm[Y + perm[Z]]].dot3(x - 1, y, z)
    var n101 = gradP[X + 1 + perm[Y + perm[Z + 1]]].dot3(x - 1, y, z - 1)
    var n110 = gradP[X + 1 + perm[Y + 1 + perm[Z]]].dot3(x - 1, y - 1, z)
    var n111 = gradP[X + 1 + perm[Y + 1 + perm[Z + 1]]].dot3(
      x - 1,
      y - 1,
      z - 1
    )

    // Compute the fade curve value for x, y, z
    var u = fade(x)
    var v = fade(y)
    var w = fade(z)

    // Interpolate
    return lerp(
      lerp(lerp(n000, n100, u), lerp(n001, n101, u), w),
      lerp(lerp(n010, n110, u), lerp(n011, n111, u), w),
      v
    )
  }
})(this)
